Crystalline silico-titanates (CSTs) are synthetic zeolites designed by Sandia National Laboratories (SNL) scientists to selectively capture radioactive cesium and other groupI metals.

They are particularly effective at capturing cesium from high salinity aqueous solutions, including seawater.

When the huge earthquake and tsunami struck Japan on March 11, 2011, leading to the Fukushima Daiichi nuclear power plant accident, it was quickly determined that CSTs would be an excellent material to be used for the removal of radioactive cesium from contaminated seawater that had been used to cool the plant’s reactors. Quick action by SNL and its corporate partner UOP, a Honeywell company, led to licensing and deployment of the technology in Japan in just a few months. Today it continues to be used to clean up cesium-contaminated water at the Fukushima power plant.

Their tests showed that CSTs outperformed other materials for cesium removal from seawater under the conditions in Japan.

The SNL team worked around the clock for 10 days to show that the technology worked in seawater. Their tests showed that CSTs outperformed other materials for cesium removal from seawater under the conditions in Japan. These results were given to the Department of Energy (DOE), and then several interactions between Honeywell UOP and SNL took place that resulted in an exclusive license to Honeywell UOP for the use of CSTs in the field of radiation waste applications.

Honeywell UOP has put the CSTs in its IONSIV™ Selective Media product line, and is using them in the cleanup effort. To date, more than 60 million gallons of cesium-contaminated seawater used to cool the Daiichi reactors after the accident rendered the reactor cooling systems inoperable has been treated using CSTs manufactured by Honeywell UOP.

The technology transfer of the CST technology to Honeywell UOP has led to more collaboration with SNL on other materials. Honeywell UOP has also recently announced an investment of $20 million to expand its production facility to produce adsorbents and catalysts, including CSTs.